This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. As part of an NIH-sponsored study, we are studying whether exercise can slow the growth of abdominal aortic aneurysms (AAA). So far, we have imaged 42 AAA patients at the Lucas Center 1.5T MR scanner. We used a 3D gadolinium-enhanced magnetic resonance angiography (MRA) sequence to image the lumen of the aorta and nearby branch vessels and a cardiac gated 1-component phase contrast sequence (PC-MRI) to measure blood flow velocity perpendicular to the aorta at the supraceliac (SC) and infrarenal (IR) levels. The MRAs were then used to construct a 3-D computer models of the AAAs, while the PC-MRI data was used to derive boundary conditions that describe flow and pressure conditions at the inlets and outlets of the AAA models. Computational simulation of blood flow in the AAAs were performed by solving the incompressible Navier-Stokes equations using a finite-element technique.